It should come as no surprise that the ad inventory on social networks like Facebook are not worth much. A new offer by Lookery, a startup that places ads on social apps inside Facebook and Bebo, is offering a guaranteed ad rate of 12.5 cents for every thousand impressions (CPM). The promotion, which runs through April is probably close to what Lookery can get for ads it places on Facebook. Add in 2 cents per thousand impressions for serving the ads and you get to about a 15 cent CPM. That is probably a good average for the bulk of inventory on Facebook, which makes up the vast majority of Lookery’s business.

This is a market-share play for Lookery. By offering a guaranteed rate, it hopes to attract enough application publishers to get to a billion impressions a month, up from 170 million in December. Lookery is smaller than the other major social-app ad networks, like Slide, RockYou, and Social Media. On social networks, more so even than on the Web in general, advertising is obviously a volume game. And Lookery is trying to catch up to the larger app ad networks, which may very well have higher average CPM rates, by taking all the low-hanging penny inventory that is out there.

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